This invention relates to an improvement to water treatment systems, especially, what are commonly referred to as water softening systems. Water hardness refers to the presence of polyvalent cations such as calcium and magnesium cations in water. Water is softened by removing these cations.
Water softening occurs by running water through an ion exchange resin. The ion exchange resin replaces the calcium and magnesium cations in the water with sodium cations. As the ion exchange resin gives up its sodium cations and becomes loaded with calcium and magnesium cations, it eventually loses its capacity to soften water and the ion exchange resin must be replenished with sodium cations. The process by which the capacity of the ion exchange resin to soften water is restored and the sodium ions are replenished is referred to as regeneration.
In regeneration, brine, a concentrated or saturated salt solution, is passed through the ion exchange resin and the cations in the ion exchange resin are replaced with sodium ions. In this way, the relatively expensive ion exchange resin may be used repeatedly in the softening process.
The conventional water softening system includes a brine tank which serves as a source of brine. Brine is produced by adding water to the brine tank which contains a salt. The brine is then removed and used to regenerate the ion exchange resin.
As the salt is consumed during this process, it is necessary that salt be periodically added to the brine tank. This invention provides a device and method for alerting the operator of the water treatment system when salt should be added.
Most modern systems do not include a low salt level sensor. The operator must remember to periodically check the level of salt in the brine tank and add salt as needed. These systems are susceptible to operator forgetfulness and error and thus are not entirely satisfactory. As the salt is necessary for the proper functioning of the system and adding salt is the only regular maintenance most modern systems need, this invention will help eliminate or dramatically reduce failure of the system due to operator error.
Previous attempts to incorporate a low salt level sensor were not satisfactory. A weight was used in an attempt to determine the level of solid salt in the brine tank. The weight was supposed to sit on top of the solid salt at the bottom of the tank. One of the problems with sensors of this type is that, when operators would add salt to the brine tank, salt would be poured over the weight and it would be buried and be unable to rise and sense the correct salt level. As a result, the sensing unit would falsely indicate that salt was needed. In addition, the salt level did not drop in a uniform manner and the salt would become unevenly distributed and the sensing device would falsely indicate that salt was needed when an adequate supply was present.
The present invention avoids these problems by placing the level sensing device within the brine tank in an area where, under normal operating conditions, it should only be in contact with the liquid brine solution.
An object of the present invention is to provide a low salt level sensor which will alert the operator when salt is needed automatically.
Another object of the present invention is to provide a low salt level sensor that is easy and economical to construct and is simple in operation.
Other objects and advantages of the present invention will become apparent as the description proceeds.